OzEMedicine - Wiki for Australian Emergency Medicine Doctors

see also:

• neurology
• paraesthesiae or numbness
• anatomy of the autonomic nervous system
• Wikipedia: Dermatome chart
• Wikipedia: innervation of upper limbs

• to detect the presence of a CNS lesion causing extremity weakness:
  • the simplest, most rapid & subtle test is for “drift”:
    • the sitting patient is asked to close his eyes & hold his arms out horizontally with palms up for 30secs.
      • if weakness is present, the hand & arm on the affected side will slowly drift or pronate.
    • lie pt prone with knees bent 90deg. and legs pointing vertically up for 30secs
      • a weak leg will tend to drift & drop
  • another sensitive test for extremity weakness is hand grasp, & foot plantar and dorsiflexion
    • test hand grasp using both hands with examiner's hands crossed in front of him so that one can test pt's ulnar side which is more reliable than radial aspect.
• if abnormal results or peripheral nerve or muscle injury, then more formal testing is needed.

• as with other aspects of the neuro. exam., if abnormal findings or specific symptoms then more detailed testing is indicated.
• testing for pain sensation is best done by double simultaneous stimulation (as for trigeminal nerve)
  • to exclude CNS lesions, if testing on dorsum of hands & feet is normal no further testing for pain is needed
• double simultaneous stimulation with gauze or wisp of cotton wool can be used to test light touch
  • NB. light touch is usually spared in unilateral spinal cord lesions
• testing for isolated nerve injuries:
  • 2 point discrimination with paper clip ends, normal is 2-8mm on fingertips & up to 75mm on upper arm & thigh
• proprioception is the most sensitive & easiest test for post. column pathway deficits
  • move great toe up or down & ask pt which way you moved (upper limb not usually needed to be tested)
• stereognosis is dependent on touch & position sense as well as post. column & sensory cortex function:
  • ask pt to identify a familiar object placed in palm (eg. key or paper clip)
• vibration sense is often the 1st sensation lost in peripheral neuropathies such as alcoholism or diabetic:
  • place vibrating tuning fork over DIP jt of a finger & the great toe, ask pt to tell you when vibration disappears.
  • if sense is absent, move to a more proximal joint

• document as: 0 = absent; 1+ = diminished; 2+ = normal; 3+ = hyperactive; 4+ = hyperactive with clonus;
• symmetric hyporeflexia may be normal or due to sedation, hypercalcaemia
• asymmetric reflexes indicate neurologic or muscular dysfunction.
• to evaluate the L4-5 nerve root (as in disc prolapse) test power of extensor hallucis longus
• +ve Babinski reflex (up-going plantar reflex) indicates an upper motor neuron lesion

• cerebellar function:
  • place finger on nose test with each hand & eyes closed (or finger to examiner's finger then to pt's nose, eyes open)
  • heel-to-shin testing with each leg (ankle to knee and back again)
  • rapid alternating movements eg. touch each fingertip with thumb; supinate/pronate hand; tap floor with foot;
• balance is a function of vision, vestibular sense and proprioception, 2 must be intact to maintain balance:
  • Romberg test - stand with feet together
    • pt with vestibular deficit will report vertigo
    • close eyes if proprioceptive deficit, pt will sway ⇒ +ve Romberg's
  • tandem gait (heel-toe walking) is sensitive but not specific test of balance.